This is a Service Truck, and the Box is really heavy, so I won't be removing it for this axle swap.
I don't want to be doing this from under the truck, so I set-up kind of a jig to line everything on the Eaton up.
I nailed 2x6's to my shop floor so they won't budge.
I traced the Eaton's Trailing arm perches U-Bolt holes.
Then I will use this for getting CaptainFab's new Perches lined up on Corp 14-Bolt to match the Eaton perch location.

I scribed and cut a piece of scrap particle board at the angle that I will need for setting the 14-Bolt at the same angle as the Eaton.
I'm done for the day, - I took 3 advil, and will likely sleep good tonight.

Your well into your conversion and too bad you don't live closer to me, I have an extra GMC 1 ton frame that would have been lots less work.
GMC 63-66 came only with leaf springs and my 14 bolt 3.42 geared rear out of a 79 diesel GMC bolted right in.
The front suspension did too.

Attached Images

__________________

Building Genuine Pontiac Firepowered cars and trucks for several decades.

Why Pontiac?? That's just me daring to be different.

Projects..

61 C40 crew cab dually under construction and of course, motivated by Pontiac.

I went ahead and put new shoes, cylinders, springs, and seals on this 14-bolt as long as I was putting it in. It's all mounted and u-bolts torqued to 175.
I went ahead and put in new u-joints also.
Emergency brake cable is also all hooked up.
All I have left is the the brake lines, and then bleeding.
I will do that this weekend.

My wife is anxious for me to get this thing rolling so I can go get 3 tons of wood pellets for the winter - they're on sale at wilco.
Yeah, Sure... she says the truck is ugly, but still wants me to get it going to take care of things on her honey-do list.

I also hope to get out to see jimmydean next week to pick up his rear bumper.

That is correct. You will not need a inner rocker in addition to that piece. I'm really glad they came out with that piece for our trucks. That one piece covers the majority of the rust issues with our trucks without having to buy 2 floor sections and only use a portion of each. This piece also makes it easier to keep that area straight, versus welding 2 pieces together.

I put a 79 front suspension clip in my 66 and the wheel/tire look like they sit in the same spot. But then again we are talking 3/4" per side differance. I had the motor out on my first swap and in on the second.
Definately easier with no motor.

__________________

Building Genuine Pontiac Firepowered cars and trucks for several decades.

Why Pontiac?? That's just me daring to be different.

Projects..

61 C40 crew cab dually under construction and of course, motivated by Pontiac.

I put a 79 front suspension clip in my 66 and the wheel/tire look like they sit in the same spot. But then again we are talking 3/4" per side differance. I had the motor out on my first swap and in on the second.
Definately easier with no motor.

I will have to do mine with the motor in.
Right now, with the new 13" brakes on the 14bolt, the truck is stopping great. So I'll probably wait until the front brakes need replacing before doing the swap.Posted via Mobile Device

I put a 79 front suspension clip in my 66 and the wheel/tire look like they sit in the same spot. But then again we are talking 3/4" per side differance. I had the motor out on my first swap and in on the second.
Definately easier with no motor.

I will have to do mine with the motor in.
Right now, with the new 13" brakes on the 14bolt, the truck is stopping great. So I'll probably wait until the front brakes need replacing before doing the swap.Posted via Mobile Device

I used a cross member for a trans under the balancer, left the top bolts on the motor mount perches and the motor mounts bloted up so the motor wouldn't tip over.
I unbolted the lower bolts for the perches that attach to the cross member.
After pulling everything out I found out all I had to do was swap A arms with spindals and rotors... etc....
3/4 to 3/4 is a direct swap.

__________________

Building Genuine Pontiac Firepowered cars and trucks for several decades.

Why Pontiac?? That's just me daring to be different.

Projects..

61 C40 crew cab dually under construction and of course, motivated by Pontiac.

I used a cross member for a trans under the balancer, left the top bolts on the motor mount perches and the motor mounts bloted up so the motor wouldn't tip over.
I unbolted the lower bolts for the perches that attach to the cross member.
After pulling everything out I found out all I had to do was swap A arms with spindals and rotors... etc....
3/4 to 3/4 is a direct swap.

Thanks.

From the threads I've read, I had just figured I'd swap the whole front cross member. But your post got me thinking; I searched the forums and found a couple threads on the subject:

After checking auto-zone, checker O'Riely's and NAPA I found the same part number for 63 3/4 ton and 79 3/4 ton A-arm shafts. In fact they used the same A arms for over 20 years.
They bolt directly in. They are the same upper and lower. I have a 79 1/2 ton suspension that bolted directly to my 63 cross member with no problem whatsoever.
I have no idea as to the interchangeability between 1/2 and 3/4 ton.
The reason I had to use the cross member on the 66 is because I used the 79 motor mount plates and the contour and hole pattern is different on the different year cross members where the plates bolt on. The 79 plates made my Pontiac transformation a bolt in deal.
If I hadn't used a Pontiac motor in my build I may have opted to leave the cross member in and not change it at all.
Frankly, you could pull your spindles only and bolt them to the 63-66 A arms.
I could do that swap in 3 hours total.

__________________

Building Genuine Pontiac Firepowered cars and trucks for several decades.

Why Pontiac?? That's just me daring to be different.

Projects..

61 C40 crew cab dually under construction and of course, motivated by Pontiac.

After checking auto-zone, checker O'Riely's and NAPA I found the same part number for 63 3/4 ton and 79 3/4 ton A-arm shafts. In fact they used the same A arms for over 20 years.
They bolt directly in. They are the same upper and lower. I have a 79 1/2 ton suspension that bolted directly to my 63 cross member with no problem whatsoever.
I have no idea as to the interchangeability between 1/2 and 3/4 ton.
The reason I had to use the cross member on the 66 is because I used the 79 motor mount plates and the contour and hole pattern is different on the different year cross members where the plates bolt on. The 79 plates made my Pontiac transformation a bolt in deal.
If I hadn't used a Pontiac motor in my build I may have opted to leave the cross member in and not change it at all.
Frankly, you could pull your spindles only and bolt them to the 63-66 A arms.
I could do that swap in 3 hours total.

Thanks for all the research and advice.
I may just go that route.
Either way, I'm going to wait until the rainy season to do the front.